JPS5940860B2 - adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to adhesive compositions, and more particularly to improved adhesive compositions having strong adhesion to both metals, glass, ceramics, and polyolefins. be.

Polyolefins such as polyethylene and polypropylene have no polarity in their molecules and are highly crystalline, so
Generally, it is difficult to bond with metal.

For this reason, there is currently a demand for adhesives that have strong adhesion to both polyolefins and metals in various applications.O Such adhesives can be obtained by hydrolyzing ethylene-methacrylate copolymers. copolymer,
Alternatively, copolymers containing carboxyl groups and mainly consisting of ethylene such as ethylene-maleic acid copolymers (Japanese Patent Publication No. 42-6178) or DuPont's Surlyn 165
2. Sedafax 1680 from Tau Chemical Co., Ltd. is known.

However, these adhesives are still insufficient for certain uses, such as the production of laminated sheathed cables, and there is a desire for adhesives with even higher adhesive performance. That is, adhesives such as Surlyn and Cedafax cannot be said to have sufficiently satisfactory adhesion to metals, but they are especially insufficient in adhesion to polyolefins. On the other hand, polyolefins that have good adhesive properties include ethylene/vinyl acetate copolymers and ethylene/acrylic acid ester copolymers, but these have extremely insufficient adhesive properties to metals. Therefore, when actually adhering metal and polyolefin firmly, there are methods that compensate for the drawbacks of each, such as a method using a two-layer film made by laminating Surlyn and ethylene-vinyl acetate copolymer, or a method that uses metal and polyolefin. A method has been devised in which the surface is first coated with Surlyn and then coated with ethylene-vinyl acetate copolymer.

However, these methods have the drawback of requiring complicated and economically disadvantageous steps such as forming a two-layer film and applying two coats. The present inventors have conducted intensive research to improve the shortcomings of conventional adhesives and develop adhesives that can firmly adhere to both metals and polyolefins. We discovered that a composition made by mixing an olefin copolymer with special functional groups and a certain type of hydrocarbon resin has strong adhesion to both polyolefin and metals, glass, and ceramics. The invention has been completed.

That is, an object of the present invention is to provide a novel adhesive composition that has strong adhesion to both polyolefin and metals, glass, and ceramics. The present invention includes (4)
(B) an ethylene copolymer containing at least one functional group selected from the group consisting of a carboxylic acid group, an acid anhydride group, and an epoxy group in polyethylene, an ethylene-unsaturated ester copolymer, or an ethylene-α-olefin copolymer; The present invention relates to an adhesive composition formed by mixing a polymer and (C) a vinyl aromatic hydrocarbon polymer or a halogenated ethylene polymer.

In the present invention, the polyethylene used as component (4) refers to low-density polyethylene produced by high-pressure radical polymerization or medium-density and high-density polyethylene produced by ionic polymerization.

In the present invention, the ethylene-unsaturated ester copolymer used as component (4) includes ethylene-vinyl ester copolymers such as ethylene-vinyl acetate copolymer, ethylene-vinyl propionate copolymer, and ethylene-acrylic ester copolymer. Ethylene-unsaturated carboxylic acid ester copolymers such as ethyl acid copolymer and ethylene-methyl methacrylate copolymer can be mentioned. Also, ethylene-α
Examples of the olefin copolymer include ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-pentene-1 copolymer, and ethylene-4-methylpentene-1 copolymer.
Examples include copolymers, ethylene-hexene-1 copolymers, ethylene-heptene-1 copolymers, ethylene-octene-1 copolymers, and the like. The melt index of polyethylene or ethylenically unsaturated ester copolymers or ethylene-α-olefin copolymers is O. 1-500
1 is particularly preferably in the range of 0.5 to 30, and in the case of an ethylene copolymer, the ethylene content is preferably 50 mol% or more, particularly 80 to 99.5 mol%.
When comparing polyethylene and ethylene copolymer, it is preferable to use ethylene copolymer in order to obtain high adhesive strength, although it differs depending on the use and intended purpose. Particularly suitable are ethylene-vinyl acetate copolymers and ethylene-ethyl acrylate copolymers. The ethylene copolymer containing at least one or more of a carboxylic acid group, an acid anhydride group, and an epoxy group used as component (B) in the following invention includes ethylene-α. β-monounsaturated carboxylic acid copolymer, ethylene-α. β-monounsaturated carboxylic acid anhydride copolymer and ethylene-α. Examples include β-monounsaturated epoxy copolymers.

α to be copolymerized with ethylene. Specific examples of β-unsaturated carboxylic acids include acrylic acid, metatallylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, etc. Examples of β-unsaturated carboxylic acid anhydrides include maleic anhydride, itaconic anhydride, citraconic anhydride, etc. Examples of the β-unsaturated epoxy include glycidyl acrylate and bricidyl methacrylate. α in the ethylene binary copolymer used as component (B). β-unsaturated carboxylic acid or α. β
Monounsaturated carboxylic acid anhydride or α. The content of β-unsaturated epoxy is preferably 0.1 to 20 mol%, particularly 1 to 10 mol%. Further, in the present invention, (B
) The above-mentioned ethylene α. A modified product obtained by crosslinking a β-unsaturated carboxylic acid copolymer with a metal salt can also be used. Of course, the ethylene copolymer used as component (B) of the present invention is not limited to the above-mentioned two-component copolymer.

For example, it is also possible to use terpolymers containing unsaturated esters or α-olefins as the third component. Examples of unsaturated esters include vinyl esters such as vinyl acetate and vinyl propionate, and unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, and methyl methacrylate. Examples of such terpolymers include ethylene-vinyl methacrylate monoacetate copolymer, ethylene-acrylic acid-ethyl acrylate copolymer, ethylene-glycidyl methacrylate-vinyl acetate copolymer, and ethylene glycidyl acrylate copolymer. Examples include r-ethyl acrylate copolymer. Also α−
Olefins include propylene, butene, benzene,
Examples include 4-methylbenzene-1, hexene, heptane, and octene. Examples of such terpolymers include ethylene-propylene acrylic acid copolymer,
Mention may be made of ethylene-propylene monomaleic anhydride copolymer. In the case of such a terpolymer, in the present invention, ethylene content is 50 to 99 mol%, unsaturated carboxylic acid or its anhydride or unsaturated epoxy content is 0.1 to 20 mol%, and unsaturated ester Contains 1 to 5
Preference is given to using a terpolymer in the range of 0 mol%. These functional group-containing ethylene copolymers are produced by a known method such as high-pressure radical polymerization, solution polymerization, or emulsion polymerization, by combining ethylene, a monomer having a functional group, and optionally a third polymer such as an unsaturated ester. Although it is produced by directly polymerizing the components, it can also be produced by graft copolymerization technology as described below.

That is, a radical initiator is added to polyethylene or an ethylene monounsaturated ester copolymer or an ethylene monounsaturated ester copolymer or an ethylene monoα-olefin copolymer and a vinyl monomer having the aforementioned functional group in the presence or absence of a solvent, and the mixture is heated and stirred. Graft copolymers useful in the present invention are thereby prepared.
The vinyl aromatic hydrocarbon polymer used as component (C) in the present invention usually has 8 to 20 carbon atoms, particularly 8 to 1 carbon atoms.
It is a single or copolymer of 2 vinyl aromatic hydrocarbons, specifically polystyrene, poly-α-methylstyrene, polyvinyltriene, poly-β-methylstyrene,
Examples include polyifpropenyltriene and poly-Tent-butylstyrene.

A particularly preferred vinyl aromatic hydrocarbon polymer in the present invention is polystyrene. Further, the halogenated ethylene polymer used in the present invention has the general formula 1L2'
-1 (However, in the formula, X represents chlorine, fluorine, Rl, R2R3
indicates hydrogen, chlorine or fluorine.

), specifically, for example, tetrafluoroethylene, trifluoroethylene, vinylidene fluorade, vinyl fluorade, vinylidene chloride, vinyl chloride polymers or the above-mentioned polymers. Examples include copolymers of halogenated ethylene and ethylene. A particularly preferred halogenated ethylene polymer in the present invention is polytetrafluoroethylene. The blending amounts of each component to obtain the composition of the present invention are (A) component 10 to 95% by weight, I3) component 1 to 8
0% by weight, (O component 1 to 50% by weight, particularly preferred blending amounts are (A) component 50 to 95% by weight, (8) component 1
~50% by weight (O component: 5~20% by weight) The method of mixing each component is not particularly specified, and may be performed using known mixing techniques such as physical mixing of powdered materials and Banbury mixer. Melt-kneading techniques using , mixing rolls, extruders, etc. can be used.The strong adhesion of the composition according to the present invention to polyolefin and metals is due to
It can only be obtained by blending component (B) and component (C) with the active ingredient, and CA), (B), (
When each component is used alone, its adhesive strength is insufficient or extremely low.

In addition, in the case of a combination of two components, (B) component ten and (C) component may exhibit considerable adhesive strength, but (4) component ten (B)
It has lower adhesive strength than component (C) and is economically disadvantageous. In addition, (4) component ten (B) component and (
4) In the case of component 10 (C), almost no remarkable adhesiveness is exhibited. Examples of adherends to be bonded with the composition of the present invention include metals such as aluminum, iron, zinc, and tin, glass,
Examples include ceramics and polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene monovinyl acetate copolymer, etc., and the composition of the present invention is particularly effective as an adhesive between metals and metals and between metals and polyolefins.

The method and conditions for bonding metals to metals or metals and polyolefins using the adhesive composition obtained by the present invention are not particularly limited, and the adhesive composition of the present invention can be used to bond metals to metals or metals to polyolefins. All that is required is to insert the composition, heat it to a temperature higher than the melting temperature of the adhesive composition, and press it.

In this case, the polyolefin may be in either a solid state or a heated molten state. Further, the form of the adhesive composition is not particularly limited, and it can be used in any convenient form such as powder, film, or sheet. Of course, it is also possible to extrude coat the metal or polyolefin surface in advance. The adhesive composition of the present invention has stronger adhesion to both metals and polyolefins than conventional adhesives. and polyolefin can be strongly bonded in a simple way.

The adhesive composition of the present invention can be used in a variety of applications, and is effective for adhering aluminum and polyethylene in packaging materials, laminated sheathed cables, etc., and in adhering aluminum and plywood, arsinium and honeycomb cores, etc. in building materials. It is. Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

In the examples, the unsaturated carboxylic acid or acid anhydride content in the graft-modified resin was measured by dissolving the graft-modified resin in xylene and measuring with alcoholic KOH using phenolphthalene as an indicator. In addition, the adhesion test was conducted using test pieces having the configuration of aluminum/adhesive/polyethylene and the configuration of aluminum/adhesive/aluminum, and was evaluated by peeling off the 180 adhesive. In each test piece, aluminum was bent and peeled off at a tensile speed of 100 mTfL7 and 1n. The aluminum used is soft aluminum with a thickness of 200μ, and the polyethylene used is Mitsui Polychemical's Mirason 1250BK with a thickness of 2m77!
The sheet was used. In addition, the adhesive is heat-pressed in advance to a thickness of 1
A sheet formed into a 00μ sheet was used. Adhesion was carried out by hot pressing at a pressure of 40 kg/d and a temperature of 160° C. for 5 minutes. Examples 1 to 8, Comparative Example 1 50 parts by weight of ethylene monovinyl acetate copolymer (melt index: 3.0, vinyl acetate content: 14% by weight) as the carrier component, polystyrene (melt index: 3.0% by weight) as the component (C). 7) Polyethylene (PE) and aluminum (AO, aluminum were bonded together) using an adhesive obtained by mixing 15 parts by weight and 50 parts by weight of an ethylene copolymer having various functional groups as component (B). Time PE/A
The peel strength of 1, Al/M was measured and shown in Table 1.

In addition, PE/Al, A2/ when component (B) is not mixed.
The peel strength of Al was also measured and shown in Table 1 as Comparative Example 1. Examples 9 to 15, Comparative Example 2 75 parts by weight of ethylene monovinyl acetate copolymer (melt index 0.8, vinyl acetate content 8% by weight) as component (A) and ethylene monovinyl acetate copolymer as component I3) Combination (melt index 1
5. Vinyl acetate content 14%) was graft-modified with acrylic acid to 25 parts by weight of a graft-modified ethylene monovinyl acetate copolymer containing 2% by weight of acrylic acid (with polystyrene or polytetrafluoroethylene (Teflon as the O component) ) in the amounts shown in Table 2 to obtain various adhesive compositions, which were used to bond PE/Al, Al/A! when bonding polyethylene (PE) and aluminum (AO or aluminum together). Table 2 shows the results of measuring peel strength.

In addition, as Comparative Example 2 (PE/when O component is not confused)
Table 2 also shows the peel strength of Al and Al/Al. Examples 16-21 (13) Graft-modified ethylene with an acrylic acid content of 2% by weight, obtained by grafting acrylic acid onto an ethylene monovinyl acetate copolymer (melt index 15, vinyl acetate content 19% by weight) Vinyl monoacetate copolymer 25
parts by weight, (10 parts by weight of polystyrene as component 0 and (
4) Using an adhesive obtained by mixing 75 parts by weight of polyethylene or various ethylene copolymers as a component,
PE/Al, Al when A1, A1 and Al are bonded
The peeling strength of /Al was measured and shown in Table 3.

(Note) A-1: Low density polyethylene (melt index 3.
2, density 0.918) A-2: High density polyethylene (melt index 0.8, density 0.960) A-3: Ethylene monovinyl acetate copolymer (melt index 1.
7. Vinyl acetate content 8% by weight) A-4: Ethylene-ethyl acrylate copolymer (melt index 6, ethyl acrylate content 15% by weight) A-5: Ethylene-propylene copolymer (melt index 1) .6, propylene content 13% by weight) A-6: Ethylene-butene-1 copolymer (melt index 2.3, butene content 9% by weight)
6) Examples 22 to 27 (polystyrene 1 as O component
Using an adhesive obtained by blending 5 parts by weight of the adhesive component shown in Table 4 and the component (B), polyethylene (PE
) and aluminum (Al), or the peeling strengths of PE/Al and Al/Al when bonding aluminum together are shown in Table 4.

Claims (1)

[Claims] 1 (A) Polyethylene, ethylene-unsaturated ester copolymer or ethylene-α-olefin copolymer, (
B) an ethylene copolymer containing at least one functional group selected from the group consisting of a carboxylic acid group, an acid anhydride group, and an epoxy group; and (C) a vinyl aromatic hydrocarbon polymer or a halogenated ethylene copolymer. Adhesive composition made by mixing with a polymer.